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In the present study, the effects of sub-lethal sub-chronic doses of ibuprofen, diclofenac, and carbamazepine alone, and in combination (concentration range 0.02–60 µg/l), on the early life stages of tench (Tinca tinca) were investigated. The lower concentrations of pharmaceuticals tested (0.02, 0.2, 2 µg/l) represent the concentration values of these substances commonly present in surface waters or effluents from wastewater treatment plants. Multiple biomarkers of biotransformation, antioxidant defence systems, and lipid peroxidation were determined in fish after 35 days of exposure. The evaluated pharmaceuticals induced oxidative stress in fish both alone and in combination with each other. Generally, 60 µg/l of each single pharmaceutical influenced the activity of antioxidant enzymes significantly (P < 0.05), whereas the same concentration of these pharmaceuticals in combination (1 : 1 : 1) did not have any impact on the activity of these enzymes. However, changes in biotransformation and antioxidant enzymes were apparent if lower concentrations of these pharmaceuticals were administered in the mixture. Significant changes (P < 0.05) in the activities of glutathione reductase, glutathione peroxidase, and glutathione-S-transferase were observed even at environmental concentration ranges. A significant effect (P < 0.05) on lipid peroxidation levels was found only in the experimental group exposed to carbamazepine.

In the European Union, the use of the insecticide NeemAzal T/S (standardised variant 1% of the active ingredient azadirachtin) is authorised in organic agriculture. The objective of this study was to determine the toxic effects of NeemAzal T/S at concentrations of 3, 10, 30, and 60 mg/lon the morphometric and condition characteristics, mortality, hatching, and histopathology of early-life stages of common carp (Cyprinus carpio L.) as a non-target aquatic organism, as well as related effects of NeemAzal T/S on selected indices of oxidative stress in the same organism. The embryo-larval toxicity test was performed according to OECD Guidelines 210 (Fish, Early-life Stage Toxicity Test). NeemAzal T/S exposure induced slow hatching on the first day and increased cumulative mortality in groups exposed to the insecticide. No effect on morphometric or condition characteristics was observed after 31 days of exposure. Histopathological changes of the gills were found at the highest concentration of 60 mg/lof NeemAzal T/S. Exposure at 30 mg/lwas associated with significantly (P < 0.01) increased glutathione peroxidase and glutathione S-transferase (P < 0.05) activities compared to the control group. The content of oxidised lipids was significantly higher (P < 0.05) in the 3, 10, and 30 mg/l experimental groups than in the controls. NeemAzal T/S exerted a significant negative influence on histopathological parameters in the embryo and larvae of common carp, as well as on the indices of oxidative stress in the same organism.

Polycyclic musk compounds are commonly used in personal care products to replace expensive natural fragrances. Due to their huge consumption, they have become a part of the aquatic environment. In the present study, a two-month exposure effect of tonalide on juvenile zebrafish (Danio rerio) was investigated. We determined the vitellogenin concentration to define the potential endocrine-disrupting effect of tonalide and also analysed selected indices to evaluate the induction of oxidative stress. The environmentally relevant concentration of tonalide (i.e., 500 ng/l) caused a significant decrease in the catalase activity (P< 0.05) and a significant increase (P< 0.05) in the lipid peroxidation. An increasing lipid peroxidation was also recorded for the highest concentration group tested (i.e., 50 000 ng/l). On the other hand, no significant changes were recorded in vitellogenin in all the exposed groups. Thus, based on these results, we have not demonstrated the endocrine-disrupting activity of tonalide in zebrafish. The results of the oxidative stress indices showed a significant impairment of the antioxidant defence after the two-month tonalide exposure, which could indicate part of the adaptive response to the tonalide toxicity.

The aim of the present study was to investigate the impact of copper-based pesticides (at concentrations of copper of 20, 30, 40 and 70 µg/l) on one-year-old common carp (Cyprinus carpio L.) during 28 days of exposure. Abnormal behaviour was observed in fish exposed to 70 µg/lfrom Day14. Histological alterations were noticed only in liver in the groups exposed to 40 and 70 µg/l.Significant changes (P ˂ 0.05) in almost all haematological indices were found, especially in the group exposed to the highest concentration of copper (70 µg/l). Biochemical analysis revealed various significant (P ˂ 0.05) differences among the tested groups. Significant differences in copper tissue concentration (P ˂ 0.05) among groups were found in liver, gills and kidney. Among antioxidative enzymes, significant changes were revealed mainly in catalase and glutathione-S-transferase activity (P ˂ 0.05). In gills, metallothionein content increased significantly (P ˂ 0.05) in the group exposed to the highest copper concentration (70 µg/l) compared with the other tested groups, including the control. A significant (P ˂ 0.05) change in total glutathione content was recorded in liver and gills, although the reduced/oxidised ratio was not affected. Oxidative damage to lipids increased significantly (P ˂ 0.05) with increasing copper concentration in liver and kidney. The results demonstrate the deleterious influence of copper on common carp even at low, environmentally relevant concentrations.

The aim of the study was to compare the acute toxicity of diclofenac to juvenile and embryonic stages of the zebrafish (Danio rerio). Acute toxicity tests were performed on the aquarium fish Danio rerio, which is one of the model organisms most commonly used in toxicity testing. The tests were performed using a semi-static method according to OECD guideline No. 203 (Fish, acute toxicity test). Embryo toxicity tests were performed in zebrafish embryos (Danio rerio) in compliance with OECD No. 212 methodology (Fish, short-term toxicity test on embryo and sac-fry stages). The results were subjected to a probit analysis using the EKO-TOX 5.2 programme to determine 96hLC50 and 144hLC50 (median lethal concentration, 50% mortality after a 96 h or 144 h interval, respectively) values of diclofenac. The statistical significance of the difference between LC50 values in juvenile and embryonic stages of Danio rerio was tested using the Mann-Whitney non-parametric test implemented in the Unistat 5.1 programme. The LC50 mean value of diclofenac was 166.6 ± 9.8 mg/L in juvenile Danio rerio, and 6.11 ± 2.48 mg/L in embryonic stages of Danio rerio. The study demonstrated a statistically higher sensitivity to diclofenac (P<0.05) in embryonic stages compared to the juvenile fish.

In the present study, the effect of polycyclic musk compound tonalide (AHTN) in two concentrations was studied in male rainbow trout (Oncorhynchus mykiss, Walbaum 1792). A feeding trial was conducted with AHTN incorporated into feed granules. One concentration was environmentally relevant (854 µg/kg); the second one was 10× higher (8699 µg/kg). The fish were fed twice a day with the amount of feed at 1 % of their body weight. After an acclimatization period, the experimental phase in duration of six weeks followed. At the end of the experiment, fish were sampled and the biometrical data were recorded. Subsequently, hematological and biochemical tests, histopathological examination, analysis of oxidative stress markers and evaluation of endocrine disruption using plasma vitellogenin were performed. In conclusion, an increase of hematocrit for both AHTN concentrations was found, but no significant changes were observed in biochemical profile. Moreover, AHTN caused lipid peroxidation in caudal kidney tissue, which was confirmed by histopathological images. The long-lasting AHTN exposure could thus be harmful for maintaining homeostasis in the rainbow trout organism. However, the vitellogenin concentration seemed not to be affected by AHTN.

The aim of this study was to investigate the effects of subchronic exposure to atrazine on fish growth and the development of histopathological changes in selected organs (gill, kidney, liver) in Danio rerio. Juvenile growth tests were performed on D. rerio according to OECD method No. 215. For 28 days, fish at an initial age of 30 days were exposed to the environmental atrazine concentration commonly detected in Czech rivers (0.3 μg/L) and a range of sublethal concentrations of atrazine (3.0, 30.0 and 90.0 μg/L). The results showed decreasing growth rates and morphological changes in the liver (dystrophic lesions of hepatocytes) at 90.0 μg/L of atrazine. The environmental concentration of atrazine in Czech rivers did not have any effect on fish growth and development of histopathological changes in D. rerio. The value of NOEC was 30.0 μg/L and the value of LOEC was 90.0 μg/L.